An inline pressure sensor can include a body and a sensor body formed into one integral body, wherein a flow passage, through which a liquid such as a liquid medicine is made to flow, is formed in the body, and the sensor body detects a pressure of the liquid which is transmitted to a pressure receiving surface through a protective sheet. See Japanese Unexamined Patent Application, Publication No. 2005-207946, for example.
The pressure sensor disclosed in the above-referenced unexamined application is configured such that a sensor body is fixed to the body by a sensor holder in a state where the sensor body is mounted on an upper surface of the body, and a body cap is mounted on the upper surface of the body thus forming these members into an integral body.